/*
 * jQuery pager plugin
 * Version 1.0 (12/22/2008)
 * @requires jQuery v1.2.6 or later
 *
 * Example at: http://jonpauldavies.github.com/JQuery/Pager/PagerDemo.html
 *
 * Copyright (c) 2008-2009 Jon Paul Davies
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Read the related blog post and contact the author at http://www.j-dee.com/2008/12/22/jquery-pager-plugin/
 *
 * This version is far from perfect and doesn't manage it's own state, therefore contributions are more than welcome!
 *
 * Usage: .pager({ pagenumber: 1, pagecount: 15, buttonClickCallback: PagerClickTest });
 *
 * Where pagenumber is the visible page number
 *       pagecount is the total number of pages to display
 *       buttonClickCallback is the method to fire when a pager button is clicked.
 *
 * buttonClickCallback signiture is PagerClickTest = function(pageclickednumber) 
 * Where pageclickednumber is the number of the page clicked in the control.
 *
 * The included Pager.CSS file is a dependancy but can obviously tweaked to your wishes
 * Tested in IE6 IE7 Firefox & Safari. Any browser strangeness, please report.
 */
(function($) {

	$.fn.pager = function(options) {

		var opts = $.extend( {}, $.fn.pager.defaults, options);

		return this.each(function() {

			// empty out the destination element and then render out the pager
			// with the supplied options
				$(this).empty().append(
						renderpager(parseInt(options.pagenumber),
								parseInt(options.pagecount),
								options.buttonClickCallback));

				// specify correct cursor activity
				$('.pages li').mouseover(function() {
					document.body.style.cursor = "pointer";
				}).mouseout(function() {
					document.body.style.cursor = "auto";
				});
			});
	};

	// render and return the pager with the supplied options
	function renderpager(pagenumber, pagecount, buttonClickCallback) {

		// setup $pager to hold render
		var $pager = $('<ul class="pages"></ul>');

		// add in the previous and next buttons
		$pager
			.append(
						renderButton('<', pagenumber, pagecount,
								buttonClickCallback));

		// pager currently only handles 5 viewable pages ( could be easily
		// parameterized, maybe in next version ) so handle edge cases
		var startPoint = 1;
		var endPoint = 5;

		if (pagenumber > 2) {
			startPoint = pagenumber - 2;
			endPoint = pagenumber + 2;
		}

		if (endPoint > pagecount) {
			startPoint = pagecount - 3;
			endPoint = pagecount;
		}

		if (startPoint < 1) {
			startPoint = 1;
		}

		// loop thru visible pages and render buttons
		/*
		for ( var page = startPoint; page <= endPoint; page++) {

			var currentButton = $('<li class="page-number">' + (page) + '</li>');

			page == pagenumber ? currentButton.addClass('pgCurrent')
					: currentButton.click(function() {
						buttonClickCallback(this.firstChild.data);
					});
			currentButton.appendTo($pager);
		}*/
		$pager.append('<li class="page-number"><span style="color:darkRed">' + pagenumber + '</span>/'+pagecount+'</li>');

		// render in the next and last buttons before returning the whole
		// rendered control back.
		$pager
				.append(
						renderButton('>', pagenumber, pagecount,
								buttonClickCallback));

		return $pager;
	}

	// renders and returns a 'specialized' button, ie 'next', 'previous' etc.
	// rather than a page number button
	function renderButton(buttonLabel, pagenumber, pagecount,
			buttonClickCallback) {

		var $Button = $('<li class="pgNext">' + buttonLabel + '</li>');

		var destPage = 1;

		// work out destination page for required button type
		switch (buttonLabel) {
		case "第一页":
			destPage = 1;
			break;
		case "<":
			destPage = pagenumber - 1;
			break;
		case ">":
			destPage = pagenumber + 1;
			break;
		case "尾页":
			destPage = pagecount;
			break;
		}

		// disable and 'grey' out buttons if not needed.
		if (buttonLabel == "第一页" || buttonLabel == "<") {
			pagenumber <= 1 ? $Button.addClass('pgEmpty') : $Button
					.click(function() {
						buttonClickCallback(destPage);
					});
		} else {
			pagenumber >= pagecount ? $Button.addClass('pgEmpty') : $Button
					.click(function() {
						buttonClickCallback(destPage);
					});
		}

		return $Button;
	}

	// pager defaults. hardly worth bothering with in this case but used as
	// placeholder for expansion in the next version
	$.fn.pager.defaults = {
		pagenumber : 1,
		pagecount : 1
	};

})(jQuery);
